Why is this happening. It doesn´t matter what I will name the int. The compiler says that this "already is defined in Form1.obj" but this is not true as I can change it to whatever and still have this compile Error ?

Thanks. Is it not possible to just declare ints, doubles, bools like you do within a Form in this Onefile.h. Like:

int Number100 = 0;
bool Word100 = false;

Why I am asking again is because I can almost be 100% sure about it should be possible because I did this for about 2 weeks ago for a whole day, so I remember it quite well and now when I do it, it does not work.
I declared ints and doubles and also bools like usual/above.
I might be wrong though. ( To point out, the OneFile.h is emty except of the declarations above)

in OneFile.h you have to declare that variable with the extern keyword extern int Number100; Then in one of the *.cpp files int Number100 = 0;

Thanks. Is it not possible to just declare ints, doubles, bools like you do within a Form in this Onefile.h. Like:

int Number100 = 0;
bool Word100 = false;

No, you can't initialize variables in a .h file. and if you omit the extern keyword you will get multiple declarations errors if the .h file is included in two or more *.cpp files.

Why I am asking again is because I can almost be 100% sure about it should be possible because I did this for about 2 weeks ago for a whole day, so I remember it quite well and now when I do it, it does not work.

I will try to explain the whole scenario what I will do, to get the right picture.
I do have this OneFile.h with this contents only:

#define Value Time == 1800

So, Value does exist in Form3 as a criteria. Now in OneFile.h I have told that
Value is Time == 1800 and this works fine.

Yes that works because it doesn't declare any variables.

What I really want to do in this OneFile.h(which also is my question if it is possible) is to make a bool out of it like:

#define Value result
bool result() {return Time == 1800;}

So result "contains" Time == 1800 in this case.
Is this possible to do in any way ?

When a function is put in a c++ header file its normally called an inline function. If the function is not part of a class then use the inline keyword so that the compiler doesn't attempt to define it multiple times.

The compiler says that Time and Input1 is undeclared identifier. These are declared within Form3 though where I have ´Value´ but doesn´t recognices in OneFile.h.
What could be needed to do here.
Thanks...

So I want result to "contain" Time == Input1. In Form3 in my project Time and Input1 is declared.

Then in Form3.cpp I have declared Time and Input1 like below.
Am I doing correct here, because with result in the macro above it wont compile but If I instead write Time == Input1 there, it do compile and works as expected.
I do want to write result as I have done though.

I have a 2d matrix with dimension (3, n) called A, I want to calculate the normalization and cross product of two arrays (b,z) (see the code please) for each column (for the first column, then the second one and so on).
the function that I created to find the ...

Write a C program that should create a 10 element array of random integers (0 to 9). The program should total all of the numbers in the odd positions of the array and compare them with the total of the numbers in the even positions of the array and indicate ...